How to Order HYDAC Parts & Motor Controls: A 5-Step Checklist for Procurement

Who This Checklist Is For

If you're the person in your company who gets handed a note that says "we need a HYDAC filter catalog" or "spec out a servo motor gearbox" — with no further context — this is for you. In 2020 I took over purchasing for a 150-person industrial equipment manufacturer. I manage roughly $1.2 million annually across 8 vendors. What I didn't know then (but learned the hard way) is that ordering industrial motor controls and hydraulic parts isn't like buying office supplies. This checklist covers the 5 things I wish someone had told me on day one.

Here's what we'll cover: identify the real need, match specs to part numbers, check compatibility, confirm lead times, and handle the paperwork. Oh, and I'll throw in a few mistakes I've made so you don't repeat them.

Step 1: Clarify What You're Actually Buying

When someone says "get me a DC motor" — don't just search for "DC motors." You’ll get 10,000 results. The first time I did that, I ordered a 24V motor when the application needed 180V.  (Should mention: I’d assumed low voltage was safer. It wasn't — the machine couldn't even start.)

Ask these three questions before touching any HYDAC catalog or supplier site:

• What machine/application is it for? That tells you voltage, torque, speed range.
• Is it a replacement or new install? Replacements need the exact original part number. New installs give you more flexibility.
• Are there any existing specs? Pump flow rate, pressure rating, filter micron rating — get them in writing.

For instance, when we needed a servo motor gearbox for a conveyor upgrade, the engineer initially said "just get a 5:1 ratio." I asked to see the motor nameplate. Turned out the servo motor was 400W, not 750W. That ratio would've oversped the output.  Moral: always double-check the motor rating.

Step 2: Use the Right Cataloging Tools

HYDAC has a massive product range — filters, pumps, valves, sensors, plus industrial motors and drives. Trying to find the right spare part without a proper methodology is a recipe for frustration.  I made this mistake: I searched "hydac filter catalog" and just picked the first result. Ordered a replacement filter element that was one micron off.  The machine ran fine for two weeks, then started overheating.  Cost us $600 in labor to re-bleed the system.

Here’s what works:

• Use the official HYDAC part number system. Filter elements start with “RET” or “E” prefixes; pumps have “P” series. Cross-reference the original part with the “hydac industrial spare parts” search on their site.
• PDF catalogs are your friend. Download the filter catalog PDF — it has spec tables that web pages sometimes miss.
• When in doubt, call tech support. I know, it's old school. But they’ll confirm which filter element fits which housing, or whether a gear pump’s shaft seal is compatible with mineral oil vs. phosphate ester.

Step 3: Verify Motor & VFD Compatibility

This step trips up a lot of buyers — myself included. I once ordered a nice servo motor gearbox (high-torque, planetary, the works) and a separate VFD.  The VFD could only control induction motors, not servo motors.  I didn't discover it until the electrician tried to wire it.  Two days of downtime.

If your order involves "how VFD control motor speed" — and yours probably will — check these:

• Motor type: Is it a standard induction motor, a servomotor, or a DC motor? VFDs work with AC induction and permanent magnet motors. DC motors need DC drives, not VFDs.
• Voltage and frequency: A 60Hz motor on a 50Hz supply will run slower and hotter. Most VFDs can compensate, but the motor nameplate limits matter.
• Enclosure rating: If it's going in a dusty shop floor, you need IP54 or higher. A standard open-drip motor will fail fast.

For DC motors, things are simpler: voltage and current rating are critical. A 90V DC motor running at 180V will burn out quickly.  I learned that when I ordered a DC motor for a conveyor table without reading the drive specs.  Smoke came out.  Literally.

Step 4: Check Lead Times & Ordering Minimums

This is where the administrative buyer earns their keep. You can have the perfect part number, but if it's on 12-week lead time and your maintenance team needs it next Tuesday, you've got a problem.

Here’s my routine after I have a list of parts:

• Check stock availability on HYDAC’s portal. Most filter elements and common gear pumps are in stock. Special servo motor gearbox configurations? Maybe 6 weeks.
• Ask about minimum order quantities. I once ordered 5 replacement filter sets but only needed 2.  Had to eat the extra $150 in inventory that sat on a shelf for a year.
• Get a firm delivery date in writing — not a “typical lead time.” If the vendor says “usually 2 weeks,” push back: “What’s the current lead time for this specific part number?”

One more thing: freight.  FOB origin vs. destination matters for cost. For a $10,000 servo motor gearbox, shipping can be $200–$500. Get it quoted separately.

Step 5: Complete the Audit Trail

Finance will thank you later. After ordering HYDAC industrial spare parts or motor controls, make sure you have:

• Purchase order with part numbers, quantities, prices.
• Confirmation of delivery terms and taxes.
• Manufacturer warranty details. HYDAC usually offers 12 months on filters, 24 months on pumps and motors.
• Invoicing format. I learned this the hard way: a vendor who couldn't provide a proper invoice cost me $2,400 in rejected expenses.  The receipt was hand-written.  Finance rejected it.  I had to pay from the department budget.

Also, save the catalog page or spec sheet you used. If the part fails, you'll need to prove what was ordered vs. what was delivered.

Common Mistakes & How to Avoid Them

• Not checking filter compatibility. HYDAC filter elements have different media types (paper, glass fiber, stainless steel).  A higher beta ratio isn't always better; it might restrict flow.
• Assuming VFDs are universal. Some VFDs only work with specific motor brands or require a dV/dt filter for long cable runs.  Ask your application engineer.
• Forgetting about accessories. For servo motor gearboxes, you often need an adapter flange, key, or encoder feedback cable.  These are sold separately.
• Skipping the physical inspection upon arrival. I once accepted a DC motor without checking the shaft diameter.  It was 0.5mm undersized.  The coupling wouldn't fit.  Return process took 3 weeks.

The most frustrating part of this job: even when you follow all the steps, things still go wrong.  After the third late delivery from a vendor, I was ready to give up.  What finally helped was building in buffer time — ordering two weeks before the need date, not one week.

When I started, I thought the lowest price was the most important metric.  Now, after 5 years of managing these relationships, I know that a reliable vendor with accurate documentation is worth the extra 10%.  That $50 saved on a filter element can cost you $500 in downtime if it's wrong.

You’ve got this.  Take these five steps, stick to the routine, and your internal customers — the engineers and maintenance teams — will start trusting your orders.  That trust is worth more than any catalog price.